U.S. patent number 7,946,102 [Application Number 11/719,105] was granted by the patent office on 2011-05-24 for functional elastic composite yarn, methods for making the same and articles incorporating the same.
This patent grant is currently assigned to Textronics, Inc.. Invention is credited to Stacey B. Burr, George W. Coulston, Eleni Karayianni, Thomas A. Micka.
United States Patent |
7,946,102 |
Karayianni , et al. |
May 24, 2011 |
**Please see images for:
( Certificate of Correction ) ** |
Functional elastic composite yarn, methods for making the same and
articles incorporating the same
Abstract
A functional elastic composite yarn comprises an elastic member
that is surrounded by at least one functional covering filament(s).
The functional covering filament has a length that is greater than
the drafted length of the elastic member such that substantially
all of an elongating stress imposed on the composite yarn is
carried by the elastic member. The elastic composite yarn may
further include an optional stress-bearing member surrounding the
elastic member and the functional covering filament.
Inventors: |
Karayianni; Eleni (Geneva,
CH), Coulston; George W. (Pittsburgh, PA), Burr;
Stacey B. (West Lafayette, IN), Micka; Thomas A. (West
Grove, PA) |
Assignee: |
Textronics, Inc. (Wilmington,
DE)
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Family
ID: |
35517250 |
Appl.
No.: |
11/719,105 |
Filed: |
November 8, 2005 |
PCT
Filed: |
November 08, 2005 |
PCT No.: |
PCT/IB2005/003338 |
371(c)(1),(2),(4) Date: |
July 16, 2008 |
PCT
Pub. No.: |
WO2006/051380 |
PCT
Pub. Date: |
May 18, 2006 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20090139601 A1 |
Jun 4, 2009 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60627169 |
Nov 15, 2004 |
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Current U.S.
Class: |
57/225 |
Current CPC
Class: |
D02G
3/328 (20130101); Y10T 428/2915 (20150115) |
Current International
Class: |
D02G
3/02 (20060101) |
Field of
Search: |
;57/210,212,213,225,239,230,3 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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10242785 |
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Apr 2004 |
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DE |
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03027365 |
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Apr 2003 |
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WO |
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2004097089 |
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Nov 2004 |
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WO |
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Primary Examiner: Hurley; Shaun R
Attorney, Agent or Firm: Connolly Bove Lodge & Hutz
LLP
Claims
What is claimed is:
1. A functional elastic composite yarn, comprising: at least one
elastic member having a relaxed unit length L and a drafted length
of (N.times.L), wherein N is in the range of about 1.0 to about
8.0; and at least one functional covering filament around the
elastic member, the functional covering filament having a length
that is greater than the drafted length of the elastic member,
wherein the functional covering filament adds at least one property
to the yarn selected from the group consisting of biological,
electrical, optical, magnetic, thermoresponsive, sensory and
actuation properties, such that a portion of an elongating stress
imposed on the composite yarn is carried by the elastic member.
2. The functional elastic composite yarn of claim 1, wherein N is
in the range of about 1.0 to about 5.0.
3. The functional elastic composite yarn of claim 1, wherein the at
least one functional covering filament has a breaking strength of
less than about 4 N at breaking elongation of less than about
30%.
4. The functional elastic composite yarn of claim 1, wherein the at
least one functional covering filament comprises a hollow
fiber.
5. The functional elastic composite yarn of claim 1, wherein the at
least one functional covering filament comprises a particle-polymer
composite.
6. The functional elastic composite yarn of claim 1, wherein the at
least one functional covering filament is a filament with a yield
point or a yield strength of less than about 4 N at a yield
elongation of less than about 30%.
7. The functional elastic composite yarn of claim 1, wherein the at
least one functional covering filament has a sheath-core structure,
wherein the sheath comprises a material selected from the group
consisting of a polyester, a nylon, a polyolefin, and an acrylic,
and mixtures of the same, and the core imparts the desired
functionality.
8. The functional elastic composite yarn of claim 1, wherein the at
least one functional covering filament has a sheath-core structure,
wherein the core comprises a material selected from the group
consisting of a polyester, a nylon, a polyolefin, and an acrylic,
and mixtures of the same, and the sheath imparts the desired
functionality.
9. The functional elastic composite yarn of claim 1, wherein the at
least one elastic member has a predetermined elastic limit, the at
least one functional covering filament has a predetermined break
elongation, and the composite yarn has an available elongation
range that is greater than the break elongation of the at least one
functional covering filament and less than the elastic limit of the
at least one elastic member.
10. The functional elastic composite yarn of claim 1, wherein the
at least one elastic member has a predetermined elastic limit, the
at least one functional covering filament has a predetermined break
elongation, and the composite yarn has an elongation range from
about 10% to about 800%.
11. The functional elastic composite yarn of claim 1, wherein the
at least one functional covering filament has a predetermined
breaking strength, and wherein the composite yarn has a breaking
strength greater than the breaking strength of the at least one
functional covering filament.
12. The functional elastic composite yarn of claim 1, wherein the
at least one functional covering filament comprises a
non-functional inelastic synthetic polymer yarn having a functional
fiber thereon.
13. The functional elastic composite yarn of claim 1, wherein the
at least one functional covering filament is wrapped in turns about
the elastic member, such that for each relaxed unit length (L) of
the elastic member there is at least one (1) to about 10,000 turns
of the functional covering filament.
14. The functional elastic composite yarn of claim 1, wherein the
at least one functional covering filament is sinuously disposed
about the elastic member such that for each relaxed unit length (L)
of the elastic member there is at least one period of sinuous
covering by the functional covering filament.
15. The functional elastic composite yarn of claim 1, further
comprising a second functional covering filament around the elastic
member, the second functional covering filament having a length
that is equal to or greater than the drafted length of the elastic
member.
16. The functional elastic composite yarn of claim 15, wherein the
second functional covering filament is (a) a composite comprising a
polymer matrix selected from the group consisting of a polyester, a
nylon, a polyolefin, and an acrylic, and a sufficiently high
loading of particulates, or (b) is a hollow fiber, and wherein the
breaking strength of the second functional covering filament is
lower than breaking strength of the functional composite yarn.
17. The functional elastic composite yarn of claim 15, wherein the
second functional covering filament has a breaking elongation that
is lower than the breaking elongation of the functional composite
yarn.
18. The functional elastic composite yarn of claim 16, wherein the
second functional covering filament comprises a non-functional
inelastic synthetic polymer yarn comprising a functional fiber.
19. The functional elastic composite yarn of claim 15, wherein the
second functional covering filament is wrapped in turns about the
elastic member, such that for each relaxed unit length of the core
there is at least one (1) to about 10,000 turns of the second
functional covering filament.
20. The functional elastic composite yarn of claim 15, wherein the
second functional covering filament is sinuously disposed about the
elastic member such that for each relaxed unit length (L) of the
elastic member there is at least one period of sinuous covering by
the second functional covering filament.
21. The functional elastic composite yarn of claim 1, wherein
substantially all of the elongating stress imposed on the composite
yarn is carried by the elastic member.
22. The functional elastic composite yarn of claim 1, further
comprising: a stress-bearing member around the elastic member,
wherein the stress-bearing member has a total length less than the
length of the functional covering filament and greater than, or
equal to, the drafted length (N .times.L) of the elastic member,
such that a portion of the elongating stress imposed on the
composite yarn is carried by the stress-bearing member.
23. The functional elastic composite yarn of claim 22, wherein
substantially all of the elongating stress imposed on the composite
yarn is carried by the stress-bearing member.
24. The functional elastic composite yarn of claim 22, wherein the
stress-bearing member comprises an inelastic synthetic polymer
yarn.
25. The functional elastic composite yarn of claim 22, wherein the
stress-bearing member is wrapped in turns about the elastic member
such that for each relaxed unit length (L) of the elastic member
there is at least one (1) to about 10,000 turns of stress-bearing
member.
26. The functional elastic composite yarn of claim 22, wherein the
stress-bearing member is sinuously disposed about the elastic
member such that for each relaxed unit length (L) of the elastic
member there is at least one period of sinuous covering by the
stress-bearing member.
27. The functional elastic composite yarn of claim 24, wherein the
stress-bearing member further comprises: a second inelastic
synthetic polymer yarn surrounding the elastic member, and wherein
the second inelastic synthetic polymer yarn has a total length less
than the length of the functional covering filament and greater
than, or at most equal to, the drafted length of (N.times.L) of the
elastic member, such that a portion of the elongating stress
imposed on the composite yarn is carried by the second inelastic
synthetic polymer yarn.
28. The functional elastic composite yarn of claim 27, wherein the
second inelastic synthetic polymer yarn is wrapped in turns about
the elastic member such that for each relaxed unit length (L) of
the elastic member there is at least one (1) to about 10,000 turns
of each inelastic synthetic polymer yarn.
29. The functional elastic composite yarn of claim 27, wherein the
second inelastic synthetic polymer yarns is sinuously disposed
about the elastic member such that for each relaxed unit length (L)
of the elastic member there is at least one period of sinuous
covering by each inelastic synthetic polymer yarn.
30. A method for forming a functional elastic composite yam,
comprising: (1) providing: (a) an elastic member having a relaxed
length; and (b) at least one nonmetallic functional covering
filament; (2) drafting the elastic member; (3) placing the
functional covering filament substantially parallel to and in
contact with the drafted length of the elastic member; and (4)
allowing the elastic member to relax to entangle the elastic member
and the functional covering filament to form the composite yarn,
wherein the at least one functional covering filament adds at least
one property to the yarn selected from the group consisting of
biological, electrical, optical, magnetic, thermo-responsive,
sensory and actuation properties.
31. The method of claim 30, wherein the method further comprises
providing a second functional covering filament, placing the second
functional covering filament substantially parallel to and in
contact with the drafted length of the elastic member; and allowing
the elastic member to relax to entangle the second functional
covering filament with the elastic member and the functional
covering filament.
32. The method of claim 30, wherein the method further comprises
providing an inelastic synthetic polymer yarn, placing the
inelastic synthetic polymer yarn substantially parallel to and in
contact with the drafted length of the elastic member; and allowing
the elastic member to relax to entangle the inelastic synthetic
polymer yarn with the elastic member and the first functional
covering filament.
33. The method of claim 32, wherein the method further comprises
providing a second inelastic synthetic polymer yarn, placing the
second inelastic synthetic polymer yarn substantially parallel to
and in contact with the drafted length of the elastic member; and
allowing the elastic member to relax to entangle the second
inelastic synthetic polymer yarn with the elastic member, the
functional covering filament, and the first inelastic synthetic
polymer yarn.
34. A method for forming a functional elastic composite yarn,
comprising: (1) providing: (a) an elastic member having a relaxed
length; and (b) at least one non-metallic functional covering
filament, wherein the functional covering filament adds at least
one property to the yarn selected from the group consisting of
biological, electrical, optical, magnetic, thermoresponsive,
sensory and actuation properties; (2) drafting an elastic member;
(3) twisting the functional covering filament with the drafted
elastic member; and (4) allowing the elastic member to relax.
35. The method of claim 34, wherein the method further comprises
providing a second functional covering filament, twisting the
second functional covering filament with the drafted elastic member
and the first functional covering filament; and allowing the
elastic member to relax.
36. The method of claim 35, wherein the method further comprises:
providing an inelastic synthetic polymer yarn, twisting the
inelastic synthetic polymer yarn with the elastic member and the
functional covering filament; and allowing the elastic member to
relax.
37. The method of claim 36, wherein the method further comprises:
providing a second inelastic synthetic polymer yarn, twisting the
second inelastic synthetic polymer yarn with the elastic member,
the functional covering filament, and the first inelastic synthetic
polymer yarn; and allowing the elastic member to relax.
38. A method for forming a functional elastic composite yarn,
comprising: (1) providing: (a) an elastic member having a relaxed
length; and (b) at least one non-metallic functional covering
filament, wherein the functional covering filament adds at least
one property to the yarn selected from the group consisting of
biological, electrical, optical, magnetic, thermoresponsive,
sensory and actuation properties; (2) drafting the elastic member;
(3) wrapping the functional covering filament about the drafted
length of the elastic member; and (4) allowing the elastic member
to relax.
39. The method of claim 38, wherein the method further comprises:
providing a second functional covering filament, wrapping the
second functional covering filament about the drafted length of the
elastic member and the first functional covering filament; and
allowing the elastic member to relax.
40. The method of claim 38, wherein the method further comprises
providing an inelastic synthetic polymer yarn, wrapping the
inelastic synthetic polymer yarn about the drafted length of the
elastic member and the functional covering filament; and allowing
the elastic member to relax.
41. The method of claim 40, wherein the method further comprises
providing a second inelastic synthetic polymer yarn, wrapping the
second inelastic synthetic polymer yarn about drafted length of the
elastic member, the functional covering filament, and the first
inelastic synthetic polymer yarn; and allowing the elastic member
to relax.
42. A method for forming a functional elastic composite yarn,
comprising: (1) providing: (a) an elastic member having a relaxed
length; and (b) at least one functional covering filament, wherein
the functional covering filament adds at least one property to the
yarn selected from the group consisting of biological, electrical,
optical, magnetic, thermoresponsive, sensory and actuation
properties; (2) forwarding the elastic member through an air jet;
(3) within the air jet, covering the elastic member with the
functional covering filament; and (4) allowing the elastic member
to relax.
43. The method of claim 42, wherein the method further comprises
providing a second functional covering filament,within the air jet,
covering the elastic member and the first functional covering
filament with a second functional covering filament; and allowing
the elastic member to relax.
44. The method of claim 42, wherein the method further comprises
providing an inelastic synthetic polymer yarn,within the air jet,
covering the elastic member and the functional covering filament
with an inelastic synthetic polymer yarn; and allowing the elastic
member to relax.
45. The method of claim 44, wherein the method further comprises
providing a second inelastic synthetic polymer yarn, within the air
jet, covering the elastic member, the functional covering filament
and the first inelastic synthetic polymer yarn with a second
inelastic synthetic polymer yarn; and allowing the elastic member
to relax.
46. A fabric comprising a plurality of functional elastic composite
yarns, wherein each functional elastic composite yarn comprises: an
elastic member having a relaxed unit length L and a drafted length
of (N.times.L), wherein N is in the range of about 1.0 to about
8.0; and at least one functional covering filament around the
elastic member, the functional covering filament having a length
that is equal to or greater than the drafted length of the elastic
member, wherein the functional covering filament adds at least one
property to the yarn selected from the group consisting of
biological, electrical, optical, magnetic, thermoresponsive,
sensory and actuation properties such that substantially all of an
elongating stress imposed on the composite yarn is carried by the
elastic member.
47. The fabric of claim 46, wherein one or more of the composite
yarns further comprise: an inelastic synthetic polymer yarn
surrounding the elastic member, and wherein the inelastic synthetic
polymer filament yarn has a total length less than the length of
the functional covering filament, such that a portion of the
elongating stress imposed on the composite yarn is carried by the
inelastic synthetic polymer yarn.
48. The functional elastic composite yarn of claim 1, wherein N is
about 1.2 to about 4.0.
Description
FIELD OF THE INVENTION
The present invention relates to elastified yarns containing
functional filaments with tensile properties that are inadequate
for textile applications, a process for producing the same, and to
stretch fabrics, garments, and other articles incorporating such
yarns.
BACKGROUND OF THE INVENTION
Fibers with functional properties have been disclosed for use in
textile yarns. Such fibers may be added for the purpose of
achieving a particular visual aesthetic, biological function, e.g.,
antimicrobial activity, thermal buffering effect, e.g., via
incorporation of phase-changing materials into the fiber structure,
electrical function, e.g., piezoelectric, electrostrictive,
electrochromic activity, optical function, e.g., photonic crystal
fibers, photoluminesce, luminescence, magnetic function e.g.,
magnetostrictive activity, thermoresponsive function, e.g., via
shape memory polymers or alloys, or sensorial function, e.g.,
chemical, bio, capacitive, acoustic sensory activity. Such
functional composite yarns have been fabricated into fabrics,
garments and wearable/apparel articles.
Functional filaments can have inadequate tensile properties for
textile manufacture or use. In many cases, a functional textile
yarn is not based solely on functional filaments or on a
combination yarn where the functional filaments are required to be
a stressed member of the yarn. This can be due, for example, to the
presence of particulates which have been added to a filament to
impart the functionality. In such cases, the particle addition can
increase fiber rigidity and/or decrease the breaking strength or
decrease the yield strength. Alternatively, functionality may be
achieved in such a way that the elastic limit of the functional
filament is reduced, such that the fiber can no longer withstand
the tensile stresses applied to fibers during conventional textile
manufacturing processes.
U.S. Published Pat. Appln No. 2004/0209059 A1, discloses a
functional composite yarn containing standard textile fibers and
antimicrobial fibers. The standard textile fibers used in this
composite functional yarn can, for example, include textile fibers
such as nylon, polyester, cotton, wool, and acrylic. Such textile
fibers have little or substantially no inherent elasticity. In
other words, these standard textile fibers do not impart "stretch
and recovery" power to the functional composite yarn. Although the
composite yarn of this reference is a functional yarn, textile
materials made therefrom would not be expected to provide textile
fabrics and constructions therefrom having a stretch potential.
Similarly, WO 03/027365, to Haggard et al., discloses a functional
fabric comprising phase-change material containing fibers. This
reference discloses functional fibers comprising a sheath made from
polyamides, polyesters and mixtures disclosed therein and including
other synthetic polymers and a core made from a combination of
hydrocarbon waxes, oils, fatty acid esters, and other phase-change
materials disclosed therein. While fabrics made from such yarns may
have satisfactory phase-changing properties; they would not be
expected to possess an inherent elastic stretch and recovery
property.
Yarns, fabrics or garments that have both stretch and recovery as
well as some other advanced functionality are highly desired. The
stretch and recovery property, or "elasticity", is the ability of a
yarn or fabric to elongate in the direction of a biasing force (in
the direction of an applied elongating stress) and return
substantially to its original length and shape, substantially
without permanent deformation, when the applied elongating stress
is relaxed. In the textile arts it is common to express the applied
stress on a textile specimen (e.g., a yarn or filament) in terms of
(a) a force per unit of cross section area of the specimen or (b)
force per unit linear density of the unstretched specimen. The
resulting strain (elongation) of the specimen is expressed in terms
of a fraction or percentage of the original specimen length. A
graphical representation of stress versus strain is the
stress-strain curve, which is well-known in the textile arts.
The degree to which fiber, yarn or fabric returns to the original
specimen length prior to being deformed by an applied stress is
called "elastic recovery" In stretch and recovery testing of
textile materials, it is also important to note the elastic limit
of the test specimen. The "elastic limit" is the stress load above
which the specimen shows permanent deformation. The available
elongation range of an elastic filament is that range of extension
throughout which there is no permanent deformation. The elastic
limit of a yarn is reached when the original test specimen length
is exceeded after the deformation-inducing stress is removed.
Typically, individual filaments and multifilament yarns elongate
(strain) in the direction of the applied stress. This elongation is
measured at a specified load or stress. In addition, it is useful
to note the elongation at break of the filament or yarn specimen.
This breaking elongation is that fraction of the original specimen
length to which the specimen is strained by an applied stress,
which ruptures the last component of the specimen filament or
multifilament yarn. Generally, the drafted length is given in terms
of a draft ratio equal to the number of times a yarn is stretched
from its relaxed unit length.
In view of the foregoing, functional textile yarns with elastic
recovery properties that can be processed using traditional textile
means to produce knitted or woven fabrics ("functional textile
yarns") continue to be sought. Fabrics and garments substantially
constructed from elastic functional yarns can provide stretch and
recovery characteristic to the entire construction, thus better
conforming to any shape, any shaped body, or requirement for
elasticity.
SUMMARY OF THE INVENTION
The present invention is directed to a functional elastic composite
yarn that comprises an elastic member having a relaxed unit length
L and a drafted length or (N.times.L). The elastic member itself
comprises one or more filaments with elastic stretch and recovery
properties. The elastic member is surrounded by at least one, but
preferably a plurality of two or more, functional covering
filament(s). Each functional covering filament has a length that is
greater than the drafted length of the elastic member such that
substantially all of an elongating stress imposed on the composite
yarn is carried by the elastic member. The value of the number N is
in the range of about 1.0 to about 8.0; and, more preferably, in
the range of about 1.0 to about 5.0, most preferably in the range
of about 1.0 to about 4.0.
The term "functional covering filament" refers to one or more
fibers that has at least one functionality or exhibits at least one
property that extends beyond mechanical properties commonly
associated with textile fibers. Functionalities or properties
associated with such members can, for example, include: biological
activities; thermoresponsive activities; optical activities, such
as light transmission, reflection, illumination or luminescence;
activity under electrical, or magnetic fields; ability to convert
energy from one form to another by responding to a stimuli;
sensory, monitoring or actuation applications; and/or any other
application or functionality referred to above. The functional
covering filament may further include: piezoelectric,
electrostrictive, ferroelectric, magnetostrictive, photonic, or
electrochromic fibers.
Each of the functional covering filament(s) may take any of a
variety of forms. The functional covering filament may be in the
form of a particulate containing composite polymeric fiber.
Alternatively the functional filament may take the form of a
functional multi-component or multi-constituent inelastic synthetic
polymeric fiber. Any combination of the various forms may be used
together in a composite yarn having a plurality of functional
covering filament(s).
Each functional filament is wrapped in turns about the elastic
member such that for each relaxed (stress free) unit length (L) of
the elastic member there is at least one (1) to about 10,000 turns
of the functional covering filament. Alternatively, the functional
covering filament may be sinuously disposed about the elastic
member such that for each relaxed unit length (L) of the elastic
member, there is at least one period of sinuous covering by the
functional covering filament.
The composite yarn may further comprise one or more inelastic
synthetic polymer yarn(s) surrounding the elastic member. Each
inelastic synthetic polymer filament yarn has a total length less
than the length of the functional covering filament, such that a
portion of the elongating stress imposed on the composite yarn is
carried by the inelastic synthetic polymer yarn(s). Preferably, the
total length of each inelastic synthetic polymer filament yarn is
greater than or equal to the drafted length (N.times.L) of the
elastic member.
One or more of the inelastic synthetic polymer yarn(s) may be
wrapped about the elastic member (and the functional covering
filament) such that for each relaxed (stress free) unit length (L)
of the elastic member there is at least one (1) to about 10,000
turns of inelastic synthetic polymer yarn. Alternatively, the
inelastic synthetic polymer yarn(s) may be sinuously disposed about
the elastic member such that for each relaxed unit length (L) of
the elastic member there is at least one period of sinuous covering
by the inelastic synthetic polymer yarn.
The composite yarn of the present invention has an available
elongation range from about 10% to about 800%, which is greater
than the break elongation of the functional covering filament and
less than the elastic limit of the elastic member, and a breaking
strength greater than the breaking strength of the functional
covering filament.
The present invention is also directed to various methods for
forming a functional elastic composite yarn.
A first method includes the steps of drafting the elastic member
used within the composite yarn to its drafted length, placing each
of the one or more functional covering filament(s) substantially
parallel to and in contact with the drafted length of the elastic
member, and thereafter allowing the elastic member to relax thereby
entangling the elastic member and the functional covering
filament(s). If the functional elastic composite yarn includes one
or more inelastic synthetic polymer yarn(s), such inelastic
synthetic polymer yarn(s) are placed substantially parallel to and
in contact with the drafted length of the elastic member and,
thereafter, the elastic member is allowed to relax thereby
entangling the inelastic synthetic polymer yarn(s) with the elastic
member and the functional covering filament(s).
In accordance with other alternative methods, each of the
functional covering filament(s) and each of the inelastic synthetic
polymer yarn(s) (if the same are provided) are either twisted about
the drafted elastic member or, in accordance with another
embodiment of the method, wrapped about the drafted elastic member.
Thereafter, in each instance, the elastic member is allowed to
relax.
Yet another alternative method for forming an functional elastic
composite yarn in accordance with the present invention includes
the steps of forwarding the elastic member through an air jet and,
while within the air jet, covering the elastic member with each of
the functional covering filament(s) and each of the inelastic
synthetic polymer yarn(s) (if the same are provided). Thereafter,
the elastic member is allowed to relax.
It also lies within the scope of the present invention to provide a
knit or woven fabric substantially wholly constructed functional
elastic composite yarns of the present invention. Such fabrics may
be used to form a wearable garment or other fabric article.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more fully understood from the following
detailed description, taken in connection with the accompanying
drawings, which form a part of this application and in which:
FIG. 1 shows stress-strain curves for the hollow fiber of
Comparative Example 1 and, for comparison, the hollow fiber
functional elastic composite yarn of Example 1;
FIG. 2 shows stress-strain curves for the phase change continuous
filament yarn of Comparative Example 2 and, for comparison, the
phase change functional elastic composite yarn of Example 2;
FIG. 3 shows stress-strain curves for the phase change continuous
filament yarn of Comparative Example 3 and, for comparison, the
phase change functional elastic composite yarn of Example 3;
FIG. 4 shows stress-strain curves for the carbon black loaded yarn
of Comparative Example 4 and, for comparison, the functional
elastic composite yarn of Example 4;
FIG. 5 is a schematic representation of an elastic composite yarn
of the invention; and
FIG. 6 shows a schematic representation of sinuous wrapping of an
elastic member by a functional covering filament.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, functional elastic
composite yarns containing functional fibers with low elastic
limits, low tenacity at break, or both, are produced. The
functional elastic composite yarns according to the present
invention comprise an elastic member (or "elastic core") that is
surrounded by at least one functional covering filament(s). Stated
alternately, at least one functional covering filament is about or
around said elastic member in the composite. The elastic member has
a predetermined relaxed unit length L and a predetermined drafted
length of (N.times.L), where N is a number, preferably in the range
from about 1.0 to about 8.0, representing the draft applied to the
elastic member.
The functional covering filament has a length that is greater than
the drafted length of the elastic member such that, when the
composite consists of the elastic member and the functional
covering member, substantially all of an elongating stress imposed
on the composite yarn is carried by the elastic member. In other
words, substantially none of the stress is carried by the
functional covering member, thus preserving the integrity and
function of such functional covering member.
The elastic composite yarn may further include an optional
stress-bearing member around or surrounding the elastic member and
the functional covering filament. The stress-bearing member
preferably is formed from one or more inelastic synthetic polymer
yarn(s). The length of the stress-bearing member(s) is less than
the length of the functional covering filament such that a portion
of the elongating stress imposed on the composite yarn is carried
by the stress-bearing member(s).
The Elastic Member
The elastic member may be implemented using one or a plurality
(i.e., two or more) filaments of an elastic yarn, such as that
spandex material sold by INVISTA North America S.a.r.l.
(Wilmington, Del., USA, 19880) under the trademark LYCRA.RTM..
The drafted length (N.times.L) of the elastic member is defined to
be that length to which the elastic member may be stretched and
return to within about five percent (5%) of its relaxed (stress
free) unit length L. More generally, the draft N applied to the
elastic member is dependent upon the chemical and physical
properties of the polymer comprising the elastic, member and the
covering and textile process used. In the covering process for
elastic members made from spandex yarns, a draft of typically
between about 1.0 and about 8.0, more preferably about 1.0 to about
5.0, and most preferably from about 1.0 to about 4.0, is
present.
Alternatively, synthetic bicomponent multifilament textile yarns
may also be used to form the elastic member. Synthetic bicomponent
filament component polymers are typically thermoplastic. More
preferably, the synthetic bicomponent filaments are melt spun, and
most preferably the component polymers are selected from the group
consisting of polyamides and polyesters.
A preferred class of polyamide bicomponent multifilament textile
yarns includes those nylon bicomponent yarns which are
self-crimping, also called "self-texturing". These bicomponent
yarns comprise a component of nylon 66 polymer or copolyamide
having a first relative viscosity and a component of nylon 66
polymer or copolyamide having a second relative viscosity, wherein
both components of polymer or copolyamide are in a side-by-side
relationship as viewed in the cross section of the individual
filament. Self-crimping nylon yarn such as that yarn sold by
INVISTA North America S.a.r.l. under the trademark TACTEL.RTM.
T-800.TM. is an especially useful bicomponent elastic yarn.
The preferred polyester component polymers include polyethylene
terephthalate, polytrimethylene terephthalate and polytetrabutylene
terephthalate. The more preferred polyester bicomponent filaments
comprise a component of PET polymer and a component of PTT polymer,
both components of the filament may be In a side-by-side
relationship as viewed in the cross section of the individual
filament. An especially advantageous filament yarn meeting this
description is that yarn sold by INVISTA North America S.a.r.l.
under the trademark T-400.TM. Next Generation Fiber. The covering
process for elastic members from these bicomponent yarns involves
the use of less draft than with spandex.
Typically, the draft for both polyamide or polyester bicomponent
multifilament textile yarns is between about 1.0 and about 5.0 and
most preferably about 1.2 to about 4.0.
The Functional Covering Filament
In its most basic form, the functional covering filament comprises
one or a plurality (i.e., two or more) strand(s) of functional
fibers.
In an alternative form, the functional covering filament comprises
a synthetic polymer yarn having one or more functional fibers(s)
thereon. Suitable synthetic polymer yarns are selected from among
continuous filament nylon yarns (e.g., from synthetic nylon
polymers commonly designated as N66, N6, N610, N612, N7, N9),
continuous filament polyester yarns (e.g. from synthetic polyester
polymers commonly designated as PET, 3GT, 4GT, 2GN, 3GN, 4GN),
staple nylon yarns, or staple polyester yarns. Such composite
functional yarns may be formed by conventional yarn spinning
techniques to produce composite yarns, such as plied, spun or
textured yarns.
Whatever form chosen, the length of the functional covering
filament around or surrounding the elastic member is determined
according to the elastic limit of the elastic member. Thus, the
functional covering filament around or surrounding a relaxed unit
length L of the elastic member has a total unit length given by
A(N.times.L), where A is some real number greater than one (1) and
N is a number in the range of about 1.0 to about 8.0. Thus, the
functional covering filament has a length that is greater than the
drafted length of the elastic member.
An alternative form of the functional covering filament may be made
by surrounding the synthetic polymer yarn with multiple turns of a
functional fiber.
Optional Stress-Bearing Member
The optional stress-bearing member of the functional elastic
composite yarn of the present invention may be made from
nonfunctional inelastic synthetic polymer fiber(s) or from natural
textile fibers like cotton, wool, silk and linen. These synthetic
polymer fibers may be continuous filament or staple yarns selected
from multifilament flat yarns, partially oriented yarns, textured
yarns, bicomponent yarns selected from nylon, polyester or filament
yarn blends.
If utilized, the stress-bearing member around or surrounding the
elastic member is chosen to have a total unit length of
B(N.times.L), where B is some real number greater than one (1). The
choice of the numbers A (with respect to the functional covering
member) and B (with respect to the optional stress-bearing member)
determines the relative lengths of the functional covering filament
and any stress-bearing member. Where A>B, for example, it is
ensured that the conducting covering filament is not stressed or
significantly extended near its breaking elongation. Furthermore,
such a choice of A and B ensures that the stress-bearing member
becomes the strength member of the composite yarn and will carry
substantially all the elongating stress of the extension load at
the elastic limit of the elastic member. Thus, the stress-bearing
member has a total length less than the length of the functional
covering filament such that a portion of the elongating stress
imposed on the composite yarn is carried by the stress-bearing
member. The length of the stress-bearing member should be greater
than, or equal to, the drafted length (N.times.L) of the elastic
member.
The stress-bearing member is preferably nylon. Nylon yarns
comprised of synthetic polyamide component polymers, such as nylon
6, nylon 66, nylon 46, nylon 7, nylon 9, nylon 10, nylon 11, nylon
610, nylon 612, nylon 12 and mixtures and copolyamides thereof, are
preferred. In the case of copolyamides, especially preferred are
those including nylon 66 with up to 40 mole percent of a
polyadipamide, wherein the aliphatic diamine component is selected
from the group of diamines available from INVISTA North America
S.a.r.l. (Wilmington, Del., USA, 19880) under the respective
trademarks DYTEK A.RTM. and DYTEK EP.RTM..
Making the stress-bearing member from nylon renders the composite
yarn dyeable using conventional dyes and processes for coloration
of textile nylon yarns and traditional nylon covered spandex
yarns.
If the stress-bearing member is polyester, the preferred polyester
is either polyethylene terephthalate (2GT, a.k.a. PET),
polytrimethylene terephthalate (3GT, a.k.a. PTT) or
polytetrabutylene terephthalate (4GT). Making the stress-bearing
member from polyester multifilament yarns also permits ease of
dyeing and handling in traditional textile processes.
The functional covering filament and the optional stress-bearing
member can surround the elastic member in a substantially helical
fashion along the axis thereof.
The relative amounts of the functional covering filament and the
stress-bearing member (if used) are selected according to ability
of the elastic member to extend and return substantially to its
unstretched length (that is, undeformed by the extension) and on
the electrical properties of the functional covering filament. As
used herein "undeformed" means that the elastic member returns to
within about +/-five percent (5%) of its relaxed (stress free) unit
length L.
Any of the traditional textile processes for single covering,
double covering, air jet covering, entangling, twisting or wrapping
of elastic filaments with functional filament and the optional
stress-bearing member yarns is suitable for making the functional
elastic composite yarn according to the invention.
In most cases, the order in which the elastic member is surrounded
by or covered by the functional covering filament and the optional
stress-bearing member is immaterial for obtaining an elastic
composite yarn. A desirable characteristic of these functional
elastic composite yarns of this construction is their stress-strain
behavior. For example, under the stress of an elongating applied
force, the functional covering filament of the composite yarn,
which is disposed about the elastic member in multiple wraps
(typically from one turn (a single wrap) to about 10,000 turns), is
tree to extend without strain due to the external stress.
Similarly, the optional stress-bearing member, which also is
disposed about the elastic member in multiple wraps, (again,
typically from one turn (a single wrap) to about 10,000 turns) is
free to extend without significant strain. If the composite yarn is
stretched near to the break extension of the elastic member, the
stress-bearing member is available to take a portion of the load
and effectively preserve the elastic member and the functional
covering filament from breaking. The term "portion of the load" is
used herein to mean any amount from about 1% to about 99 percent of
the load, and more preferably from about 10% to about 80% of the
load; and most preferably from about 25% to about 50% of the
load.
FIG. 5 illustrates a functional elastic composite yarn 100 that has
an elastic member 40 covered by a functional covering filament 20
and a stress-bearing member 50. The functional elastic composite
yarn 100 of this embodiment was formed by twisting.
The elastic member may optionally be sinuously wrapped by the
functional covering filament and the optional stress-bearing
member. Sinuous wrapping is schematically represented in FIG. 6,
where an elastic member 40, for example, a LYCRA.RTM. yarn, is
wrapped with a functional covering filament 10, for example, a
metallic wire, in such a way that the wraps are characterized by a
sinuous period P.
Specific embodiments and procedures of the present invention will
now be described further, by way of example, as follows.
Test Methods
Measurement of Fiber and Yarn Stress-Strain Properties
Fiber and Yarn Stress-Strain Properties were determined using a
dynamometer at a constant rate of extension to the point of
rupture. The dynamometer used was that manufactured by Instron
Corp, 100 Royall Street, Canton, Mass., 02021 USA.
The test specimens were conditioned to about 22.degree. C..+-.about
1.degree. C. and about 60%.+-.about 5% R.H. The test was performed
at a gauge length of 5 cm and crosshead speed of about 50 cm/min.
Threads measuring about 20 cm were removed from the bobbin and
allowed to relax on a velvet board for at least 16 hours in
air-conditioned laboratory, A specimen of this yarn was placed in
the jaws with a pre-tension weight corresponding to the yarn dtex
so as not to give either tension or slack. The results obtained
from this method enable direct comparison between the functional
elastic composite yarn and its components. It is expected that the
pretension load influences available elongation of the yarn (that
is, at a higher pretension load a lower available elongation is
measured). Pretension load is not expected to influence the
ultimate strength of the yarn.
Measurement of Fabric Stretch
Fabric stretch and recovery for a stretch woven fabric was
determined using a universal electromechanical test and data
acquisition system to perform a constant rate of extension tensile
test. The system used was that from Instron Corp, 100 Royall
Street, Canton, Mass., 02021 USA.
Two fabric properties were measured using this instrument: (1)
fabric stretch and (2) the fabric growth (deformation). The
available fabric stretch was measured as the amount of elongation
caused by a specific load between 0 and about 30 Newtons and
expressed as a percentage change in length of the original fabric
specimen as it was stretched at a rate of about 300 mm per minute.
The fabric growth was measured as the unrecovered length of a
fabric specimen which had been held at about 80% of available
fabric stretch for about 30 minutes then allowed to relax for about
60 minutes. Where 80% of available fabric stretch was greater than
about 35% of the fabric elongation, this test was limited to about
35% elongation. The fabric growth was then expressed as a
percentage of the original length.
The elongation or maximum stretch of stretch woven fabrics in the
stretch direction was determined using a three-cycle test
procedure. The maximum elongation measured was the ratio of the
maximum extension of the test specimen to the initial sample length
found in the third test cycle at load of about 30 Newtons. This
third cycle value corresponds to hand elongation of the fabric
specimen. This test was performed using the above-referenced
universal electromechanical test and data acquisition system
specifically equipped for this three-cycle test.
EXAMPLES
Comparative Example 1
A hollow fiber based on Polyester with Nr-18/1 (360 dtex) was
examined for its stress and strain properties using the dynamometer
and with an applied pretension load of about 400 mg. This fiber is
branded Thermolite.RTM. and is a registered trademark for INVISTA,
Inc. delivering maximum warmth and protection. The stress-strain
curve of this fiber is shown in FIG. 1 at 50. This fiber exhibits a
relatively high initial modulus and a relatively low elongation at
break at less than about 30% of its test specimen length,
characterized by a relatively high ultimate strength. Notably,
where this fiber is used in textile fabrics and apparel, there is a
severe limit to the elongation available. Such a fiber in garments,
subject to stretch from movement of the wearer, would be expected
to restrict the ultimate comfort of the garment in terms of freedom
of movement.
Example 1
A 360 decitex (dtex) elastic core made of LYCRA.RTM. spandex yarn
was wrapped with the Thermolite.RTM. yarn described in Comparative
Example 1 using a standard spandex covering process. Covering was
done on an I.C.B.T. machine model G307. During this process,
LYCRA.RTM. spandex yarn was drafted to a value of 5 times (i.e.,
N=5), and was wrapped with two Thermolite.RTM. yarns of the same
type, one twisted to the "S" and the other to the "Z" direction, to
produce a hollow filament functional elastic composite yarn. The
Thermolite.RTM. yarns were wrapped at about 1000 turns/meter (turns
of Thermolite.RTM. yarn per meter of drafted Lycra.RTM. spandex
yarn) (about 5000 turns for each relaxed unit length L) for the
first covering and at about 800 turns/meter (about 4000 turns for
each relaxed unit length L) for the second covering. The
stress-strain curve 52 shown in FIG. 1 is for the hollow fiber
functional elastic composite yarn measured as in Comparative
Example 1 with an applied pretension load of about 400 mg. This
hollow fiber functional elastic composite yarn exhibits an
exceptional stretch behavior to over about 100% more than the test
specimen length and elongates to the range of about 200% before it
breaks, exhibiting a higher ultimate strength than the
Thermolite.RTM. yarns individually. This process allows production
of a hollow fiber functional elastic composite yarn that exhibits
an elongation to break in the range of about 200% and a force to
break in the range of about 700 cN, compared to the individual
Thermolite.RTM. yarn that exhibits an elongation to break of only
about 22% and a force to break of about 590 cN. As can be seen from
the characteristic stress-strain curve 52 of this example, the
break of the hollow fiber functional elastic composite yarn is
caused by the functional yarn breaking before the elastic member of
the composite yarn breaks.
Comparative Example 2
A bicomponent core-sheath fiber containing a loading of phase
change particles in the sheath was examined for its stress and
strain properties using the dynamometer and with an applied
pretension load of about 100 mg. This fiber is type D22 developed
by INVISTA, Inc. and is an 86den 34 continuous filament yarn. The
stress-strain curve 60 of this fiber is shown in FIG. 2. This fiber
exhibits a relatively high initial modulus with a yield point at
only about 5% followed by a relatively high elongation at break to
about 150% of its test specimen length. Notably, where this fiber
is used in textile fabrics and apparel, there is a severe limit to
the mechanical properties of the textile characterized by a high
toughness at the very low elongation range, which is the useful
comfort range for wearables. Such a fiber in garments, subject to
stretch from movement of the wearer, would be expected to restrict
the ultimate comfort of the garment in terms of freedom of
movement.
Example 2
A 44 decitex (dtex) elastic core made of LYCRA.RTM. spandex yarn
was wrapped with the D22 yarn described in Comparative Example 2,
using a standard spandex covering process. Covering was done on an
I.C.B.T. machine model G307. During this process, LYCRA.RTM.
spandex yarn was drafted to a value of 3.2 times (i.e., N=3.2) and
was wrapped with two D22 yarns of the same type, one twisted to the
"S" and the other to the "Z" direction, to produce a phase change
filament functional elastic composite yarn. The D22 yarns were
wrapped at about 1500 turns/meter (turns of D22 yarn per meter of
drafted Lycra.RTM. spandex yarn) (about 4800 turns for each relaxed
unit length L) for the first covering and at about 1200 turns/meter
(about 3840 turns for each relaxed unit length L) for the second
covering. The stress-strain curve 62 shown in FIG. 2 is for a phase
change fiber functional elastic composite yarn measured as in
Comparative Example 1 with an applied pretension load of about 100
mg. This phase change fiber functional elastic composite yarn
exhibits an elastic modulus to about 30% more than the test
specimen length and elongates to the range of about 300% before it
breaks, exhibiting a higher ultimate strength than the D22 yarns
individually. This process allows production of a phase change
fiber functional elastic composite yarn that exhibits an elongation
to break in the range of about 300% and a force to break in the
range of about 180 cN, compared to the individual D22 yarn that
exhibits an elongation to break of about 150% and a force to break
of about 70 cN (see FIG. 2). This process also yields a functional
composite yarn with a yield point at about 50% elongation, a range
higher than the individual D22 yarn that yields at only about 5%
elongation. This is a significant advantage for use of textiles in
that useful elongation range. As can be seen from the
characteristic stress-strain curve of this example (62 in FIG. 2),
the break of the hollow fiber functional elastic composite yarn is
caused by the functional yarn breaking before the elastic member of
the composite yarn breaks.
Comparative Example 3
A bicomponent core-sheath fiber containing a loading of phase
change particles in the sheath was examined for its stress and
strain properties using the dynamometer and with an applied
pretension load of about 50 mg. This fiber is type D22 developed by
INVISTA and is an 48den 34 continuous filament yarn. The
stress-strain curve 70 of this fiber is shown in FIG. 3. This fiber
exhibits a quite high initial modulus with a quite low elongation
at break to about 10% of its test specimen length. Notably, where
this fiber is used in textile fabrics and apparel, there is a
severe limit to the elongation available. Such a fiber in garments,
subject to stretch from movement of the wearer, would be expected
to restrict the ultimate comfort of the garment in terms of freedom
of movement.
Example 3
A 44 decitex (dtex) elastic core made of LYCRA.RTM. spandex yarn
was wrapped with the D22 yarn described in Comparative Example 3
using a standard spandex covering process. Covering was done on an
I.C.B.T. machine model G307. During this process, LYCRA.RTM.
spandex yarn was drafted to a value of 3.2 times (i.e., N=3.2), and
was wrapped with two D22 yarns of the same type, one twisted to the
"S" and the other to the "Z" direction, to produce a phase change
filament functional elastic composite yarn. The D22 yarns were
wrapped at about 1500 turns/meter (turns of D22 yarn per meter of
drafted Lycra.RTM. spandex yarn) (about 4800 turns for each relaxed
unit length L) for the first covering and at about 1200 turns/meter
(about 3840 turns for each relaxed unit length L) for the second
covering. The stress-strain curve 72 shown in FIG. 3 is for phase
change fiber functional elastic composite yarn measured as in
Comparative Example 3 with an applied pretension load of about 50
mg. This phase change fiber functional elastic composite yarn
exhibits an elastic modulus to about 50% more than the test
specimen length and elongates to the range of about 90% before it
breaks, exhibiting a higher ultimate strength than the D22 yarns
individually. This process allows production of a phase change
fiber functional elastic composite yarn that exhibits an elongation
to break in the range of about 90% and a force to break in the
range of about 280 cN, compared to the individual D22 yarn that
exhibits an elongation to break of only about 10% and a force to
break of about 80 cN. As can be seen from the characteristic
stress-strain curve 72 of this example, the break of the hollow
fiber functional elastic composite yarn is caused by the functional
yarn breaking before the elastic member of the composite yarn
breaks.
Comparative Example 4
A polyamide fiber containing a loading of carbon black particles
was examined for its stress and strain properties using the
dynamometer and with an applied pretension load of about 50 mg.
This fiber is Tactel.RTM. POY yarn, a registered trademark by
INVISTA, and is an 28den 10 filament continuous filament yarn. The
stress-strain curve 80 of this fiber is shown in FIG. 4. This fiber
exhibits a relatively high initial modulus with a subtle yield
point at about 20% elongation and with an elongation at break to
about 70% of its test specimen length. Notably, where this fiber is
used in textile fabrics and apparel, there is a severe limit to the
elongation available. Such a fiber in garments, subject to stretch
from movement of the wearer, would be expected to restrict the
ultimate comfort of the garment in terms of freedom of movement. As
a comparison in FIG. 4, there is also included the stress-strain
curve 82 of the reference fiber without the loading of carbon black
particles. It can be seen from such comparison that the loading of
the functional particles imposes a yield and reduces significantly
the ultimate strength of the fiber compared to the reference fiber
that shows a continuous increase of its stress with increasing
strain up till the breaking point.
Example 4
A 44 decitex (dtex) elastic core made of LYCRA.RTM. spandex yarn
was wrapped with the Tactel.RTM. yarn described in Comparative
Example 4 using a standard spandex covering process. Covering was
done on an I.C.B.T. machine model G307. During this process,
LYCRA.RTM. spandex yarn was drafted to a value of 3.2 times (i.e.,
N=3.2), and was wrapped with two Tactel.RTM. yarns of the same
type, one twisted to the "S" and the other to the "Z" direction, to
produce a phase change filament functional elastic composite yarn.
The Tactel.RTM. yarns were wrapped at about 1500 turns/meter (turns
of D22 yarn per meter of drafted Lycra.RTM. spandex yarn) (about
4800 turns for each relaxed unit length L) for the first covering
and at about 1200 turns/meter (about 3840 turns for each relaxed
unit length L, for the second covering. The stress-strain curve 84
shown in FIG. 4 is for a carbon black fiber functional elastic
composite yarn measured as in Comparative Example 4 with an applied
pretension load of about 50 mg. This functional elastic composite
yarn exhibits an exceptional stretch behavior to about 160% more
than the test specimen length and elongates to the range of about
280% before it breaks, exhibiting a higher ultimate strength than
the Tactel.RTM. yarns individually and a similar ultimate strength
to the reference Tactel.RTM. yarn alone. This process allows
production of a black dyed fiber functional elastic composite yarn
that exhibits an elongation to break in the range of about 280% and
a force to break in the range of about 140 cN, compared to the
individual Tactel.RTM. yarn that exhibits an elongation to break of
about 70% and a force to break of about 90 cN. As can be seen from
the characteristic stress-strain curve 84 of this example, the
break of the black functional elastic composite yarn is caused by
the functional yarn breaking before the elastic member of the
composite yarn breaks.
The examples are for the purpose of illustration only. Many other
embodiments falling within the scope of the accompanying claims
will be apparent to the skilled person.
* * * * *